Which one of the statement is incorrect?

Options

A. DNA ligases are used to cleave DNA molecule
B. Genomic DNA library is packing of donor DNA in a collection of vectors.
C. A technique of deliberate manipulating of genes /transfer or gene to a different organism is genetic engineering.
D. Plasmids are used as vectors in genetic engineering becausing of their ability to carry foreign genes

Answer

To determine which statement is incorrect, let's analyze each option provided:

1. **Statement 1**: "DNA ligase is used to cleave DNA molecules."
- **Analysis**: This statement is incorrect. DNA ligase is an enzyme that is responsible for joining DNA fragments together by forming phosphodiester bonds. It does not cleave (cut) DNA; rather, it repairs and connects DNA strands.

2. **Statement 2**: "The genomic DNA library is the packing of donor DNA in a collection of vectors."
- **Analysis**: This statement is correct. A genomic DNA library is indeed a collection of DNA fragments that have been cloned into vectors, allowing for the storage and manipulation of the donor DNA.

3. **Statement 3**: "The technique of deliberate manipulating of genes transfer of genes to a different organism is genetic engineering."
- **Analysis**: This statement is also correct. Genetic engineering involves the intentional manipulation of genes, including the transfer of genes from one organism to another.

4. **Statement 4**: "Plasmids are used as vectors in genetic engineering because of their ability to carry foreign genes."
- **Analysis**: This statement is correct as well. Plasmids are small circular DNA molecules that can replicate independently and are commonly used as vectors to introduce foreign genes into host cells.

**Conclusion**: The incorrect statement is **Statement 1**.

### Step-by-Step Solution:
1. **Identify the statements**: Read through each statement carefully to understand their meanings.
2. **Analyze Statement 1**: Recognize that DNA ligase does not cleave DNA but rather joins DNA fragments.
3. **Analyze Statement 2**: Confirm that a genomic DNA library is indeed a collection of DNA fragments in vectors.
4. **Analyze Statement 3**: Acknowledge that genetic engineering involves the manipulation and transfer of genes.
5. **Analyze Statement 4**: Understand that plasmids are used as vectors due to their ability to carry foreign genes.
6. **Determine the incorrect statement**: Conclude that Statement 1 is the only incorrect statement among the options.